Ethylene-alpha-olefin copolymer-triallyl phosphate composition

ABSTRACT

A peroxide-curable ethylene copolymer composition comprising (A) a crosslinkable ethylene/alpha-olefin copolymer, (B) an effective amount of triallyl phosphate (TAP), (C) an organic peroxide, and, optionally, (D) a supplemental polymer; wherein the (A) crosslinkable ethylene/alpha-olefin copolymer is made by copolymerizing ethylene and an olefin-functional comonomer in the presence of a molecular catalyst useful therefor. Also provided are a cured product made from the composition, methods of making and using same, and articles containing same.

The field includes ethylene/alpha-olefin copolymer compositions, curedproducts made therefrom, methods of making and using same, and articlescontaining same.

INTRODUCTION

Insulated electrical/optical conductors include insulated electricalconductors, insulated optical conductors, and insulated electro-opticalconductors. Insulated optical conductors include coated optical fibersand optical fiber (fiber optic) cables for use in data-transmittingapplications. Insulated electrical conductors include coated metal wiresand electrical cables, including power cables for use in low, medium,high and extra-high voltage electricity-transmitting/distributingapplications. Insulated electro-optical conductors include coatedoptical fibers and coated metal wires for using in data- and/orelectricity-transmitting applications.

Various types of wire and cable compositions are mentioned in U.S. Pat.Nos. 3,974,132; 7,858,705 B2; WO 2007/056154; WO 2010/017553; WO2010/017554; WO 2015/009562; WO 2016/200600 A1; PCT/US16/048014; orPCT/US16/056719.

U.S. Pat. No. 3,974,132 to L. L. Valdiserri (“VALDISERRI”) relates to aprocess for curing olefin polymers. Mentioned are heat-curable ethylenepolymer compositions wherein triallyl phosphate is used as a coagent.The composition also contains an organic peroxide catalyst. Examples ofthe ethylene polymers mentioned include a low density polyethylene(LDPE); an ethylene copolymer having a T_(g) (glass transitiontemperature) greater than 25 degrees Celsius (° C.); or anethylene-propylene-1,4-hexadiene terpolymer. Based on discoverytimeline, any catalyst used to make VALDISERRI's ethylene polymers wouldhave been Ziegler-Natta catalyst.

U.S. Pat. No. 7,858,705 B2 to J. S. Parent et al. (“PARENT”) relates tofunctionalized polyolefins, moisture curable polyolefin resins andprocesses of manufacturer (sic) thereof. In an aspect of Example 5,triallyl phosphate was included in an isotactic-polypropylenedegradation formulation, prior to the addition of 3-mercaptopropyltrimethoxysilane. The isotactic-polypropylene was in a form of pelletsand had a number average molecular weight of 50,000 and apolydispersity=3.8.

WO 2010/017554 A1 to B. Chaudhary et al. (“CHAUDHARY”; the same B.Chaudhary of the present filing) relates to polyolefin compositions withgrafted flame-retardants. CHAUDHARY includes a flame-retardantcomposition made from or containing (a) a polyolefin and (b) agraftable, phosphorous-containing coagent. CHAUDHARY also includes apolyolefin having a grafted flame retardant bonded thereto. The (b) isin an amount greater than about 1.0 weight percent up to about 20.0weight percent. Suitable graftable, phosphorous-containing coagent cansimultaneously contain phosphorous, nitrogen, and silicon elements.Among others is an example that includes a metallocene-catalyzedethylene-octene copolymer having an octene comonomeric content=7.3 molepercent. Ethylene/unsaturated ester copolymers are mentioned where theportion of the copolymer attributed to the ester comonomer is about 5 toabout 50 weight percent, preferably about 15 to about 40 weight percent,based on the weight of the copolymer. An example includes ELVAX 265, anethylene-vinyl acetate copolymer that is not made with a molecularcatalyst.

SUMMARY

We recognized that VALDISERRI's ethylene polymers, PARENT'sisotactic-polypropylene, and the 7.3 mole percent octene comonomericcontent of CHAUDHARY's metallocene-catalyzed ethylene-octene copolymerexample sometimes lack sufficient flexibility for use as a flexibleproduct, such as flexible electrical insulation. They may also lacksufficient heat or oxidative stability for use in medium-to-ultra-highvoltage power cables.

We recognized that coverings (e.g., single layer coverings or multilayercoverings) of incumbent insulated electrical/optical conductors thathave been exposed to heat for a prolonged period of time become lessflexible, are prone to oxidize and embrittle. There is a need for a newcrosslinked polyolefin material that exhibits sufficient flexibility,heat or oxidative stability, and dissipation factor for use as a singlelayer covering or multilayer covering, e.g., an improved crosslinkedpolyolefin insulation layer of the multilayer covering of the insulatedelectrical/optical conductor, especially in power cables formedium-to-ultra-high voltage applications. Our problem, then, would beto formulate a new curable polyolefin composition that, when cured,produces a new crosslinked polyolefin material that has enhanced (i.e.,increased) flexibility, enhanced (increased) heat and/or oxidativestability, and/or unchanged or less than three times worsened(increased) dissipation factor. For heat and/or oxidative stabilitycharacterization, tensile elongation retained (TER) after heat agingand/or oxidative induction time (OIT) may be measured. The TER afterheat aging may be tensile elongation retained after 7 days at 136° C. orafter 28 days at 136° C., measured according to the procedure describedlater (“TER (7 d, 136° C.)” or “TER (28 d, 136° C.)”), collectively “TER(7 d or 28 d, 136° C.)”. The oxidative induction time may be measured inmolecular oxygen atmosphere at 185° C., according to the proceduredescribed later (“OIT (O₂, 185° C.)”). As for dissipation factorcharacterization, it may be measured at 130° C., 60 Hertz (Hz), and 2kilovolts (kV) according to the procedure described later using ASTMD150, (“DF (130° C., 60 Hz, 2 kV)”).

Our technical solution to this problem includes a new peroxide-curableethylene copolymer composition (inventive composition) comprising (A) acrosslinkable ethylene/alpha-olefin copolymer, (B) an effective amountof triallyl phosphate (TAP), and (C) an organic peroxide. The (A)crosslinkable ethylene/alpha-olefin copolymer is made by a processcomprising copolymerizing ethylene and an alpha-olefin comonomer, andoptionally another comonomer selected from a non-conjugated diene and asecond alpha-olefin, in the presence of a molecular catalyst usefultherefor. Also included is a new crosslinked ethylene/alpha-olefincopolymer (inventive crosslinked product) made by curing the inventivecomposition. The inventive crosslinked product has sufficient, evenenhanced (i.e., increased), flexibility and enhanced (i.e., increased)heat and oxidative stability, and sufficient dissipation factor for useas a single layer covering or a multilayer covering, e.g., thecrosslinked polyolefin insulation layer of the multilayer covering ofthe insulated electrical/optical conductor. Our technical solution alsoincludes methods of making and using the inventive composition andarticles comprising or made from the inventive composition orcrosslinked product. The inventive composition and crosslinked productare useful for making a single layer covering or a multilayer covering,e.g., a crosslinked polyolefin insulation layer of a multilayer coveringof an insulated electrical/optical conductor. Also included is thecrosslinked polyolefin insulation layer made from the inventivecomposition or crosslinked product, the single or multilayer covering(e.g., the multilayer covering containing the crosslinked polyolefininsulation layer), and the insulated electrical/optical conductorcontaining the single or multilayer covering. The insulatedelectrical/optical conductor is useful for data- and/orelectricity-transmitting/distributing applications, including low,medium, high, and ultra-high voltage applications.

DETAILED DESCRIPTION

The Summary and Abstract are incorporated here by reference. Theinventive crosslinked product is characterized as being a TAP-graftedethylene/alpha-olefin copolymer. The copolymer is made by a free radicalprocess that forms covalent bonds between TAP molecules and the (A)crosslinkable ethylene/alpha-olefin copolymer. The free radical processinvolves free radicals that are initiated or propagated by a freeradical generator compound such as a peroxide or by other means ofgenerating free-radicals such as electron-beam irradiation. Theinventive crosslinked product or copolymer (A) may exhibit any gelcontent (as measured, for instance, by decalin extraction) ranging from0 to 100 wt %. All flexural modulus values are measured at 23° C. unlessstated otherwise.

To enable the technical solution, the effective amount of (B) TAP may befrom 0.050 to less than 0.950 weight percent (wt %) of the (B) TAP,based on total weight of the inventive composition. E.g., (B) TAP may befrom 0.050 to 0.949 wt %, alternatively 0.101 to 0.901 wt %,alternatively 0.1501 to 0.849 wt %, alternatively 0.1905 to 0.8049 wt %of the inventive composition. After the inventive composition is curedthe resulting inventive crosslinked product may be characterized by anenhanced (i.e., increased) TER (7 d or 28 d, 136° C.), an enhanced(i.e., increased) OIT (O₂, 185° C.), and an unchanged or less than threetimes worsened (i.e., <3× increased), alternatively an unchanged or lessthan two times worsened (i.e., <2× increased) DF (130° C., 60 Hz, 2 kV),all relative to a TAP-free comparative composition and TAP-freecomparative crosslinked product made therefrom. In addition, if TAP ispresent in a less TAP-containing comparative composition at >0 to lessthan 0.050 wt %, based on total weight of the less TAP-containingcomparative composition, after curing the less TAP-containingcomparative composition the resulting less-TAP comparative crosslinkedproduct may be characterized by TER (7 d or 28 d, 136° C.) or OIT (O₂,185° C.) that may not be enhanced or sufficiently enhanced (i.e.,insufficiently increased) for use in flexible electrical insulation formedium-to-ultra-high power cables. Also, if TAP is present in a moreTAP-containing comparative composition at 1.00 wt % or greater,alternatively 1.10 wt % or greater, based on total weight of the moreTAP-containing comparative composition, after curing the moreTAP-containing comparative composition the resulting more-TAPcomparative crosslinked product may be characterized by an enhanced (orfurther enhanced) TER (7 d or 28 d, 136° C.), an enhanced (or furtherenhanced) OIT (O₂, 185° C.), and an enhanced (i.e., decreased) DF (130°C., 60 Hz, 2 kV).

Aspect 1. A peroxide-curable ethylene copolymer composition comprising58.00 to 99.90 weight percent (wt %) of (A) a crosslinkableethylene/alpha-olefin copolymer (“copolymer (A)” or “constituent (A)”),which is made by a process comprising copolymerizing ethylene and analpha-olefin comonomer, and optionally another comonomer selected from anon-conjugated diene and a second alpha-olefin, in the presence of amolecular catalyst useful therefor; from 0.050 to 0.949 wt % of (B)triallyl phosphate (TAP); from 0.050 to 5.00 wt % of (C) an organicperoxide; and from 0.00 to 40 wt %, alternatively 0.00 to 20 wt %,alternatively 0.00 wt %, alternatively >0.00 to 10 wt % of (D) asupplemental polymer selected from an ethylene/unsaturated carboxylicester copolymer, a polyethylene homopolymer, a Non-(molecularcatalyst)-formed ethylene/alpha-olefin copolymer, and a propylene-basedpolymer; with the proviso that the total weight of constituent (A) andconstituent (D) is 80.00 to 99.90 wt %, alternatively 90.0 to 99.90 wt%, alternatively 90.0 to 96.5 wt %; wherein all wt % are based on totalweight of the peroxide-curable ethylene copolymer composition andwherein total weight of the peroxide-curable ethylene copolymercomposition is 100.0 wt %. When in certain embodiments a sum of the wt %of constituents (A) to (C), alternatively (A) to (D), is less than100.00 wt %, the composition further contains at least one additionalconstituent, such as constituent (D) or at least one of constituents (E)to (O), respectively, which are described later. Typically, thecopolymerizing ethylene and the alpha-olefin comonomer, and optionallyanother comonomer selected from a non-conjugated diene and a secondalpha-olefin, to make the (A) crosslinkable ethylene/alpha-olefincopolymer is done in the absence of a Ziegler-Natta catalyst.

Aspect 2. The peroxide-curable ethylene copolymer composition of aspect1 further described by any one of limitations (i) to (ii): (i) thealpha-olefin comonomer is a (C₃-C₂₀)alpha-olefin and the (A)crosslinkable ethylene/alpha-olefin copolymer is anethylene-(C₃-C₂₀)alpha-olefin copolymer (e.g., bipolymer (copolymerizingwithout the another comonomer) or terpolymer (copolymerizing with thesecond alpha-olefin comonomer)) that is characterized by at least oneof, alternatively two of, alternatively each of the properties (a) to(c): (a1) a flexural modulus (2% secant) of from >0 to 40,000 psi (>0 to278 MPa), alternatively from >0 to 6,500 psi (>0 to 45 MPa),alternatively from >0 to 5,000 psi (>0 to 34 MPa) measured according toASTM D790-15e2 and/or (a2) a density from 0.850 to 0.930 grams per cubiccentimeter (g/cm³), alternatively 0.850 to 0.890 g/cm³ measuredaccording to ASTM D792; (b) a glass transition temperature (T_(g)) of−130° to −20° C. measured by differential scanning calorimetry (DSC)according to ASTM 3418-15, and (c) a melt index (190° C., 2.16 kilograms(kg), “I₂”) of 0.5 decigram per minute (dg/min.) to 50 dg/min. measuredaccording to ASTM D1238-04; or (ii) the alpha-olefin comonomer ispropylene and the another comonomer is used and is a non-conjugated(C₆-C₂₀)diene and the (A) crosslinkable ethylene/alpha-olefin copolymeris an ethylene-propylene-(C₆-C₂₀)diene copolymer (e.g., terpolymer)(EPDM) characterized by at least one of, alternatively two of,alternatively each of the properties (a) to (d): (a1) a flexural modulus(2% secant) of from >0 to 20,000 psi (>0 to 138 MPa), alternativelyfrom >0 to 6,500 psi (>0 to 45 MPa), alternatively from >0 to 5,000 psi(>0 to 34 MPa) measured according to ASTM D790-15e2 and/or (a2) adensity from 0.850 to 0.910 g/cm³, alternatively 0.850 to 0.890 g/cm³measured according to ASTM D792; (b) a glass transition temperature(T_(g)) of −130° to −20° C. measured by differential scanningcalorimetry (DSC) according to ASTM 3418-15, (c) a melt index (190° C.,2.16 kilograms (kg), “I₂”) of 0.1 decigram per minute (dg/min.) to 50dg/min. measured according to ASTM D1238-04, and (d) a Mooney Viscosity(ML1+4 at 125° C.) from 15 to 170 measured according to ASTM D1646-15,with a 1 minute preheat time and a 4 minutes rotor operation time. Insome aspects the copolymer (A) is free of covalently bonded siliconatoms. In other aspects the copolymer (A) further contains hydrolyzablesilyl functional groups (e.g., trimethoxysilyl groups) and the copolymer(A) is characterized as being an ethylene/alpha-olefin/olefin-functionalhydrolyzable silane copolymer. Theethylene/alpha-olefin/olefin-functional hydrolyzable silane copolymermay be made as described later.

Aspect 3. The peroxide-curable ethylene copolymer composition of aspect1 or 2 further described by any one of limitations (i) to (iv): (i) the(A) crosslinkable ethylene/alpha-olefin copolymer is from 90 to 99 wt %,alternatively 91 to 98 wt %, alternatively 93 to 97 wt % of theperoxide-curable ethylene copolymer composition, and theperoxide-curable ethylene copolymer composition is free of (lacks) the(D) supplemental polymer; (ii) the (A) crosslinkableethylene/alpha-olefin copolymer is from 58.00 to 90.00 wt %,alternatively 80.0 to 90.0 wt %, alternatively 85.0 to 90.0 wt % of theperoxide-curable ethylene copolymer composition and the (D) supplementalpolymer is from 40.0 to 1.0 wt %, alternatively from 10.0 to 1.0 wt %,alternatively from 10.0 to 7.0 wt %, respectively, of theperoxide-curable ethylene copolymer composition; (iii) the (D)supplemental polymer is present and is a polypropylene homopolymer; and(iv) both (ii) and (iii). All wt % are based on total weight of theperoxide-curable ethylene copolymer composition.

Aspect 4. The peroxide-curable ethylene copolymer composition of any oneof aspects 1 to 3 further described by any one of limitations (i) to(iv): (i) the (B) triallyl phosphate (TAP) is from 0.090 to 0.940 wt %;(ii) the (B) triallyl phosphate (TAP) is from 0.100 to 0.900 wt %; (iii)the (B) triallyl phosphate (TAP) is from 0.19 to 0.849 wt %; (iv) the(B) triallyl phosphate (TAP) is from 0.200 to 0.800 wt %; wherein all wt% are based on total weight of the peroxide-curable ethylene copolymercomposition.

Aspect 5. The peroxide-curable ethylene copolymer composition of any oneof aspects 1 to 4 further described by any one of limitations (i) to(v): (i) the (C) organic peroxide is from 1.0 to 4.0 wt %, alternativelyfrom 1.5 to 3.0 wt %, alternatively from 1.9 to 2.4 wt %, all wt % basedon total weight of the peroxide-curable ethylene copolymer composition;(ii) the (C) organic peroxide is a compound of formula R^(O)—O—O—R^(O),wherein each R^(O) independently is a (C₁-C₂₀)alkyl group or(C₆-C₂₀)aryl group; (iii) the (C) organic peroxide isbis(1,1-dimethylethyl) peroxide; bis(1,1-dimethylpropyl) peroxide;2,5-dimethyl-2,5-bis(1,1-dimethylethylperoxy) hexane;2,5-dimethyl-2,5-bis(1,1-dimethylethylperoxy) hexyne;4,4-bis(1,1-dimethylethylperoxy) valeric acid; butyl ester;1,1-bis(1,1-dimethylethylperoxy)-3,3,5-trimethylcyclohexane; benzoylperoxide; tert-butyl peroxybenzoate; di-tert-amyl peroxide (“DTAP”);bis(alpha-t-butyl-peroxyisopropyl) benzene (“BIPB”); isopropylcumylt-butyl peroxide; t-butylcumylperoxide; di-t-butyl peroxide;2,5-bis(t-butylperoxy)-2,5-dimethylhexane;2,5-bis(t-butylperoxy)-2,5-dimethylhexyne-3,1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane;isopropylcumyl cumylperoxide; butyl 4,4-di(tert-butylperoxy) valerate;or di(isopropylcumyl) peroxide; or dicumyl peroxide; (iv) the (C)organic peroxide is dicumyl peroxide; and (v) a combination of (i) andany one of (ii) to (iv).

Aspect 6. The peroxide-curable ethylene copolymer composition of any oneof aspects 1 to 5 further described by limitation (i) or (ii): (i)wherein the total amount of constituents (A) to (D) is 100 wt % thereof;or (ii) wherein the total amount of constituents (A) to (D) is less than100 wt % thereof and the peroxide-curable ethylene copolymer compositionfurther comprises at least one of constituents (E) to (O): (E) anantioxidant; (F) a coagent that is not TAP; (G) a polydimethylsiloxane(PDMS) fluid; (H) a hindered amine stabilizer; (I) a flame retardant;(J) a tree retardant; (K) a colorant; (L) a liquid aromatic or saturatedhydrocarbon (LASH); (M) a methyl radical scavenger; (N) a scorchretardant; and (O) a filler. In some aspects the peroxide-curableethylene copolymer composition further comprises at least one of,alternatively each of (E) antioxidant, (F) coagent that is not TAP, (H)hindered amine stabilizer, and (J) tree retardant. In some aspects theperoxide-curable ethylene copolymer composition does not furthercomprise at least one, alternatively each of the constituents (G) PDMSfluid, (I) flame retardant, (K) colorant, (L) liquid aromatic orsaturated hydrocarbon (LASH); (M) methyl radical scavenger; (N) scorchretardant; and (O) filler.

Aspect 7. The peroxide-curable ethylene copolymer composition of aspect6 further described by any one of limitations (i) to (vi): (i) theperoxide-curable ethylene copolymer composition further comprisesconstituent (E) antioxidant and the (E) antioxidant isbis(4-(1-methyl-1-phenylethyl)phenyl)amine;2,2′-methylene-bis(4-methyl-6-t-butylphenol);2,2′-thiobis(2-t-butyl-5-methylphenol;2,2′-thiobis(6-t-butyl-4-methylphenol;tris[(4-tert-butyl-3-hydroxy-2,6-dimethylphenyl)methyl]-1,3,5-triazine-2,4,6-trione;pentaerythritoltetrakis(3-(3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl)propionate;3,5-bis(1,1-dimethylethyl)-4-hydroxybenzenepropanoic acid2,2′-thiodiethanediyl ester; or distearyl thiodipropionate; (ii) theperoxide-curable ethylene copolymer composition further comprisesconstituent (F) coagent that is not TAP and the (F) coagent that is notTAP is triallyl isocyanurate (TAIC); an unsaturated organophosphorouscompound such as triallyl phosphoric triamide,N-hydroxymethyl-3-dimethylphosphonopropionamide, 2-ethyl-methacrylatephosphoric acid, phosphate ester of hydroxyl ethyl methacrylate, orvinyl phosphonic acid; or alpha-methyl styrene dimer (AMSD) ordiisopropenylbenzene (DIPB); (iii) the peroxide-curable ethylenecopolymer composition further comprises constituent (H) hindered aminestabilizer and the (H) hindered amine stabilizer is1,3,5-triazine-2,4,6-triamine,N2,N2″-1,2-ethanediylbis[N2-[3-[[4,6-bis[butyl(1,2,2,6,6-pentamethyl-4-piperidinyl)amino]-1,3,5-triazin-2-yl]amino]propyl]-N′,N″-dibutyl-N′,N″-bis(1,2,2,6,6-pentamethyl-4-piperidinyl)-;(iv) the peroxide-curable ethylene copolymer composition furthercomprises constituent (J) tree retardant and the (J) tree retardant is apoly(ethylene glycol) (PEG) with a number-average molecular weight(M_(n)) of 10,000 to 30000 grams/mole; (v) the peroxide-curable ethylenecopolymer composition further comprises a combination of limitations (i)to (iv); and (vi) the peroxide-curable ethylene copolymer compositionfurther comprises from 0.20 to 0.50 wt % constituent (E) wherein (E) is2,2′-thiobis(2-t-butyl-5-methylphenol, from 0.30 to 0.50 wt %constituent (F) wherein (F) is alpha-methyl styrene dimer (AMSD), from0.10 to 0.30 wt % constituent (H) wherein (H) is1,3,5-triazine-2,4,6-triamine,N2,N2″-1,2-ethanediylbis[N2-[3-[[4,6-bis[butyl(1,2,2,6,6-pentamethyl-4-piperidinyl)amino]-1,3,5-triazin-2-yl]amino]propyl]-N′,N″-dibutyl-N′,N″-bis(1,2,2,6,6-pentamethyl-4-piperidinyl)-,and from 0.40 to 0.80 wt % constituent (J) wherein (J) is a PEG having aM_(n) of 15000 to 25000 g/mol.

Aspect 8. The peroxide-curable ethylene copolymer composition of any oneof aspects 1-7, wherein the (A) crosslinkable ethylene/alpha-olefincopolymer is an ethylene/propylene/diene terpolymer and the diene is5-ethylidene-2-norbornene.

Aspect 9. A method of making a peroxide-curable ethylene copolymercomposition of any one of aspects 1 to 8, the method comprisingcontacting effective amounts of constituents (A) to (C), and anyoptional constituents (D) to (O), to give the peroxide-curable ethylenecopolymer composition. In some aspects the method is conducted accordingto Preparation Method 1 described later.

Aspect 10. The method of aspect 9 wherein the contacting comprisesinternal mixing the constituents (A) to (C) and any optionalconstituents (D) to (O) or soaking at least one of the constituents (B),(C), and any optional constituents (D) to (O) into constituent (A). Thesoaking is a passive method that is free of agitating such as meltmixing.

Aspect 11. A crosslinked ethylene/alpha-olefin copolymer product that isa product of curing the peroxide-curable ethylene copolymer compositionany one of aspects 1 to 8.

Aspect 12. The crosslinked ethylene/alpha-olefin copolymer product ofaspect 11 wherein the (A) crosslinkable ethylene/alpha-olefin copolymeris an ethylene/propylene/diene terpolymer and the diene is5-ethylidene-2-norbornene and the crosslinked ethylene/alpha-olefincopolymer product has a tensile elongation from 30% to 90% after beingheated at 180° C. in an oven for 17 hours or a tensile elongationretention from 25% to 80% after being heated at 180° C. in an oven for24 hours.

Aspect 13. A manufactured article comprising a shaped form of thecrosslinked ethylene/alpha-olefin copolymer product of aspect 11 or 12.

Aspect 14. A coated conductor comprising a conductive core and aninsulation layer at least partially covering the conductive core,wherein at least a portion of the insulation layer comprises thecrosslinked ethylene/alpha-olefin copolymer product of aspect 11 or 12.The insulation layer may be a single layer covering or multilayercovering the conductive core. The coated conductor may be an insulatedelectrical conductor/optical as generally described in the Introduction,which description is hereby incorporated by reference, except whereinthe crosslinked polyolefin insulation layer of the multilayer coveringof the insulated electrical/optical conductor is comprised of theinventive crosslinked product. The inventive insulatedelectrical/optical conductor may be an insulated electrical conductorand useful for transmitting electricity.

Aspect 15. A method of conducting electricity, the method comprisingapplying a voltage across the conductive core of the coated conductor ofaspect 14 so as to generate a flow of electricity through the conductivecore.

The peroxide-curable ethylene copolymer composition (inventivecomposition, e.g., of aspects 1 to 7). The total weight of allconstituents is 100 wt %. The inventive composition is substantiallyfree of, alternatively does not contain, a polyolefin other thanconstituent (A) or constituents (A) and (D). E.g., is substantially fromor, alternatively does not contain, an ethylene/unsaturated carboxylicester copolymer, a poly(C₄-C₄₀)alpha-olefin homopolymer, or apolystyrene. Otherwise the inventive composition may contain additionalpolymers as long as any additional polymers do not completely negativethe technical solution. In this context, consisting essentially of meansthat the inventive composition contains 0 to 1 wt %, alternatively 0 to<0.1 wt %, alternatively 0 wt % of any other polymer, not countingconstituents (A) to (O).

The peroxide-curable ethylene copolymer composition contains theconstituents (A) to (C), described in more detail later. Theperoxide-curable ethylene copolymer composition contains (A)crosslinkable ethylene/alpha-olefin copolymer, which are crosslinkablemacromolecules having ethylene-derived monomeric units andalpha-olefin-derived comonomeric units. The (A) may consist of carbonand hydrogen atoms and, optionally, silicon atoms and silicon-bondedoxygen atoms. The (A) may be substantially free or free of otherheteroatoms (e.g., halogen, N, S, P). Under curing conditions (typicallycomprising heating to a temperature above 160° C., alternatively above180° C.) the (C) organic peroxide forms oxygen-radicals. The O-radicalsabstract hydrogen atoms from interior carbon atoms in backbones or sidechains of the (A) crosslinkable ethylene/alpha-olefin copolymer, therebygenerating internal polymeric chain free radicals on carbon atoms. Thecarbon radicals couple to form the crosslinked ethylene/alpha-olefincopolymer. The crosslinking occurs via a curing reaction under curingconditions, thereby forming the crosslinked ethylene/alpha-olefincopolymer, which is a networked polymer.

The peroxide-curable ethylene copolymer composition may be a one-partformulation, alternatively a two-part formulation, alternatively athree-part formulation. The one-part formulation comprises constituents(A) to (C), and any optional constituents such as constituents (D) to(O), in a single mixture, which is the peroxide-curable ethylenecopolymer composition. The two-part formulation may comprise first andsecond parts, wherein the first part consists essentially of (A)crosslinkable ethylene/alpha-olefin copolymer and, optionally, (D)supplemental polymer, and wherein the second part consists essentiallyof an additive masterbatch composition containing at least one ofconstituents (B) to (C), and any optional constituents such as additives(D) to (O). The remaining constituents (B) to (C), and any optionalconstituents such as additives (D) to (O), may be in the first part orthe second part or both. The peroxide-curable ethylene copolymercomposition may be made from the two-part formulation by combining thefirst and second parts to give an admixture thereof as theperoxide-curable ethylene copolymer composition. The three-partformulation may be the same as the two-part formulation except thatconstituent (C) and, optionally, any (G) PDMS fluid are not in the firstor second parts, but constituent (C) organic peroxide, and optionallyconstituent (G) PDMS fluid comprise(s) a third part. When (C), andoptionally (G) comprise(s) a third part, the peroxide-curable ethylenecopolymer composition may be made by combining the first and secondparts to give an admixture thereof containing constituents (A), (B), any(D), and optionally any constituents (H) to (O); if desired optionallypelletizing the admixture to give the admixture in the form of pellets;and then contacting the admixture (e.g., pellets) of the first andsecond parts with the third part (i.e., (C) organic peroxide, andoptionally (G) PDMS fluid to give the peroxide-curable ethylenecopolymer composition. Generally, the combining or mixing (contacting)of constituents (A) to (C), optionally (D), and any optionalconstituents such as additives (E) to (O), may be carried out at atemperature from about 20° to 100° C. for 2 to 100 hours, e.g., 50° to80° C. for 6 to 24 hours. Higher temperatures may be used when combiningconstituents (A), (B), optionally (D), and any constituents (E) to (O),to give an admixture in the absence of (C) organic peroxide, andthereafter the admixture may be cooled to a temperature below a curingtemperature before being combined or contacted with (C) organicperoxide. There is no inherent reason why any combination ofconstituents (A) to (C) and optional (D), and any optional constituents(D) to (O), cannot be in either the one-part formulation or the firstpart or the second part of the two-part formulation. There generallyaren't any incompatibilities amongst (A) to (O).

In some aspects the (A) crosslinkable ethylene/alpha-olefin copolymer ofany one of embodiments (i) to (i) of aspect 2 is characterized as ahydrolyzable silane-grafted crosslinkable ethylene/alpha-olefincopolymer made by post-reactor grafting of the olefin-functionalhydrolyzable silane (e.g., vinyl trimethoxysilane) onto the copolymer(A) of any one of the foregoing embodiments (i) to (ii).

In some aspects the (A) crosslinkable ethylene/alpha-olefin copolymer ofany one of embodiments (i) to (ii) of aspect 2 is characterized by atleast one of, alternatively two of, alternatively each of properties (a)to (c): (a1) flexural modulus (2% secant) from 500 to 40,000 psi (3 to276 MPa), alternatively 500 to 20,000 psi (3 to 138 MPa), alternatively500 to 6,500 psi (3 to 45 MPa), alternatively 500 to 4,501 psi (3 to 31MPa), alternatively from 500 to 4001 psi (3 to 28 MPa), alternatively500 to 3501 psi (3 to 24 MPa), alternatively 900 to 2010 psi (6 to 14MPa), all measured according to ASTM D790-15e2 and/or (a2) density of0.850 to 0.930 g/cm³, alternatively 0.850 to 0.910 g/cm³, alternatively0.850 to 0.890 g/cm³, alternatively 0.850 to 0.885 g/cm³, alternatively0.850 to 0.880 g/cm³, alternatively 0.850 to 0.875 g/cm³, alternatively0.870 to 0.875 g/cm³, all measured according to ASTM D792; (b) T_(g) is−120° to −30° C., alternatively −110° to −50° C., measured by DSCaccording to ASTM 3418-15; (c) melt index (190° C., 2.16 kilograms (kg),“I₂”) from 0.3 to 30 dg/min., alternatively 0.5 to 20.0 dg/min.,measured according to ASTM D1238-04. In some aspects the (A)crosslinkable ethylene/alpha-olefin copolymer of any one of embodiments(i) to (ii) is independently further characterized by property (e) beingcurable with dicumyl peroxide, but in absence of TAP, to a TAP-freecomparative crosslinked ethylene/alpha-olefin copolymer having a DF(130° C., 60 Hz, 2 kV) of greater than 0.1%, alternatively greater than0.3%, alternatively greater than 0.5%. In some aspects (A) ischaracterized by property (a1); alternatively property (a2);alternatively property (b); alternatively property (c); alternativelyproperties (a1) and (a2); alternatively properties (a1) or (a2) and (b);alternatively properties (a1) or (a2) and (c); alternatively properties(a1), (a2), (b), and (c).

The constituent (A): the crosslinkable ethylene/alpha-olefin copolymer.A “copolymer” is a macromolecule or collection of macromolecules havingmonomeric units, made by polymerizing a monomer, and one or moredifferent types of comonomeric units, made by polymerizing one or moredifferent alpha-olefin comonomers and optionally a non-conjugated diene.Monomers and comonomers are polymerizable molecules. A monomeric unit,also called a monomer unit or “mer”, is the largest constitutional unitcontributed by (derived from) a single monomer molecule to the structureof the macromolecule(s). A comonomeric unit is the largestconstitutional unit contributed by (derived from) a single comonomermolecule to the structure of the macromolecule(s). Each unit istypically divalent. A “bipolymer” is a copolymer made from a monomer andone comonomer. A “terpolymer” is a copolymer made from a monomer and twodifferent comonomers. An “ethylene/alpha-olefin copolymer” is such acopolymer wherein the monomeric units are derived from the monomerethylene (CH₂═CH₂) and comprise on average per molecule, at least 50weight percent of the macromolecules and the comonomeric units arederived from at least one alpha-olefin comonomer and, optionally, asecond alpha-olefin comonomer or a non-conjugated (C₆-C₂₀)diene. Eachcomonomer may independently have hydrogen atoms and from 3 to 20 carbonatoms per molecule. The (A) crosslinkable ethylene/alpha-olefincopolymer may be in a bulk form of granules or pellets.

In some of the above aspects the alpha-olefin comonomer may be a(C₃-C₂₀)alpha-olefin, alternatively a (C₄-C₂₀)alpha-olefin,alternatively a (C₄-C₈)alpha-olefin. The (A) crosslinkableethylene/alpha-olefin copolymer may be a correspondingethylene-(C₃-C₂₀)alpha-olefin copolymer (e.g., bipolymer or terpolymer),each independently characterized by the at least one of, alternativelytwo of, alternatively each of properties (a) to (c) and, optionally,(e). The ethylene-(C₃-C₂₀)alpha-olefin bipolymer consists essentially ofethylene-derived monomeric units and (C₃-C₂₀)alpha-olefin-derivedcomonomeric units. The ethylene-(C₃-C₂₀)alpha-olefin terpolymer consistsessentially of ethylene-derived monomeric units, first(C₃-C₂₀)alpha-olefin-derived comonomeric units, and second(C₃-C₂₀)alpha-olefin-derived comonomeric units. The first(C₃-C₂₀)alpha-olefin-derived comonomeric units are derived from a first(C₃-C₂₀)alpha-olefin and the second (C₃-C₂₀)alpha-olefin-derivedcomonomeric units are derived from a second (C₃-C₂₀)alpha-olefin,wherein the first and second (C₃-C₂₀)alpha-olefins are different (e.g.,the first (C₃-C₂₀)alpha-olefin is propylene and the second(C₃-C₂₀)alpha-olefin is 1-hexene). The ethylene monomeric units may befrom 99 to 51 wt %, alternatively from 95 to 60 wt %, alternatively 90to 70 wt % of the ethylene-(C₃-C₂₀)alpha-olefin bipolymer, or a singlepoint permutation thereof such as from 99 to 70 wt % or from 90 to 60 wt%. The (C₃-C₂₀)alpha-olefin comonomeric units may be from 1 to 49 wt %,alternatively 5 to 40 wt %, alternatively 10 to 30 wt % of theethylene-(C₃-C₂₀)alpha-olefin bipolymer, or a single point permutationthereof such as from 1 to 30 wt % or from 10 to 40 wt %. The wt % valuesare on average per molecule of the ethylene-(C₃-C₂₀)alpha-olefinbipolymer. The alpha-olefin comonomer contains only one carbon-carbondouble bond (C═C), which is located at a terminal carbon atom. The(C₃-C₂₀)alpha-olefin may be a (C₄-C₈)alpha-olefin and theethylene-(C₃-C₂₀)alpha-olefin copolymer may be anethylene-(C₄-C₈)alpha-olefin bipolymer characterized by the at least oneof, alternatively two of, alternatively each of properties (a) to (c)and, optionally, (e). The (C₃-C₂₀)alpha-olefin may be linear, branched,or cyclic-containing. In some aspects the (C₃-C₂₀)alpha-olefin is a(C₃-C₁₀)alpha-olefin, alternatively (C₄-C₈)alpha-olefin, alternatively(C₁₀-C₂₀)alpha-olefin. Examples of suitable (C₃-C₂₀)alpha-olefins arepropene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene,1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, and 1-octadecene. The(C₃-C₂₀)alpha-olefin is unsubstituted or substituted with a cycloalkylgroup on a saturated (spa) carbon atom such as 3-cyclohexyl-1-propeneand vinylcyclohexane. Examples of the ethylene-(C₃-C₂₀)alpha-olefinbipolymers are ethylene/propylene bipolymers, ethylene/1-butenebipolymers, ethylene/1-hexene bipolymers, and ethylene/1-octenebipolymers. Examples of the ethylene-(C₃-C₂₀)alpha-olefin terpolymersare ethylene/propylene/1-octene terpolymers, ethylene/propylene/1-buteneterpolymers, and ethylene/1-butene/1-octene terpolymers. Theethylene-(C₃-C₂₀)alpha-olefin copolymer may be an ethylene-(1-octene)bipolymer. Example of a suitable ethylene-(C₃-C₂₀)alpha-olefin copolymeris a molecular catalyst-made ethylene-1-octene copolymer characterizedby a density of 0.872 g/cm3 measured according to ASTM D792; a meltindex (190° C., 2.16 kg) of 4.8 g/10 min. measured according to ASTMD1238; a flexural modulus (2% secant) of 1570 psi (10.8 MPa) measuredaccording to ASTM D790-15e2; and a glass transition temperature (T_(g))of −53° C. measured by differential scanning calorimetry (DSC) accordingto ASTM 3418-15; obtained commercially as Developmental XUS 38660.00Polyolefin Elastomer by The Dow Chemical Company.

In some of the above aspects the comonomers used to make the (A)crosslinkable ethylene/alpha-olefin copolymer may be the combination ofpropylene and a non-conjugated (C₆-C₂₀)diene and the (A) crosslinkableethylene/alpha-olefin copolymer may be theethylene-propylene-(C₄-C₂₀)diene terpolymer (EPDM) characterized by theat least one of, alternatively two of, alternatively each of properties(a) to (d) and, optionally, (e). The EPDM consists essentially ofethylene-derived monomeric units, propylene-derived comonomeric units,and non-conjugated (C₆-C₂₀)diene-derived comonomeric units. The ethylenemonomeric units may be from 99 to 51 wt %, alternatively from 95 to 60wt %, alternatively 90 to 70 wt % of the EPDM, or a single pointpermutation thereof such as from 99 to 70 wt % or from 90 to 60 wt %.The ethylenic monomeric unit wt % may be measured according to ASTPD3900. The (C₃-C₂₀)alpha-olefin comonomeric units may be from 1 to 48.1wt %, alternatively 5 to 39.1 wt %, alternatively 10 to 29.1 wt % of theEPDM, or a single point permutation thereof such as from 1 to 39.1 wt %or from 10 to 48.1 wt %. The non-conjugated (C₆-C₂₀)diene may be from0.1 to 10.0 wt %, alternatively from 0.2 to 5.0 wt %, alternatively 0.3to 3.0 wt % of the EPDM. The wt % values are on average per molecule ofthe EPDM. The total weight of ethylene, propylene, and non-conjugated(C₆-C₂₀)diene units is 100 wt % of the EPDM. The non-conjugated(C₆-C₂₀)diene contains only two carbon-carbon double bonds. The C═C ofthe (C₄-C₂₀)diene are non-conjugated. In some aspects the non-conjugated(C₆-C₂₀)diene is a non-conjugated (C₆-C₁₅)diene, alternatively anon-conjugated (C₆-C₈)diene. Examples of suitable non-conjugated(C₆-C₂₀)dienes are 1,4-hexadiene, 1,6-octadiene, 1,7-octadiene,1,9-decadiene; branched-chain acyclic dienes, such as5-methyl-1,4-hexadiene, 3,7-dimethyl-1,6-octadiene,3,7-dimethyl-1,7-octadiene, and mixed isomers of dihydromyricene anddihydroocinene; single-ring alicyclic dienes, such as1,3-cyclopentadiene, 1,4-cyclohexadiene, 1,5-cyclooctadiene, and1,5-cyclododecadiene; and multi-ring alicyclic fused and bridged-ringdienes, such as tetrahydroindene, methyl tetrahydroindene,dicyclopentadiene, and bicyclo-(2,2,1)-hepta-2,5-diene; alkenyl,alkylidene, cycloalkenyl, and cycloalkylidene norbornenes, such as5-ethylidene-2-norbornene, 5-methylene-2-norbornene,5-propenyl-2-norbornene, 5-isopropylidene-2-norbornene,5-(4-cyclopentenyl)-2-norbornene, 5-cyclohexylidene-2-norbornene,5-vinyl-2-norbornene, and norbornadiene. In some aspects the(C₆-C₂₀)diene is 1,4-hexadiene (“HD”), 5-ethylidene-2-norbornene(“ENB”), 5-vinylidene-2-norbornene (“VNB”), 5-methylene-2-norbornene(“MNB”), or dicyclopentadiene (“DCPD”). In other aspects thenon-conjugated (C₆-C₂₀)diene is 1,4-hexadiene, or 1,7-octadiene. Thenon-conjugated (C₆-C₂₀)diene may be 1,4-hexadiene, 1,6-hexadiene,dicyclopentadiene, ethylidene norbornene, or vinyl norbornene; and the(A) crosslinkable ethylene/alpha-olefin terpolymer may be anethylene-propylene-1,4-butadiene terpolymer characterized by the atleast one of, alternatively two of, alternatively each of properties (a)to (d) and, optionally, (e); an ethylene-propylene-1,4-hexadieneterpolymer characterized by the at least one of, alternatively two of,alternatively each of properties (a) to (d) and, optionally, (e); anethylene-propylene-1,6-hexadiene terpolymer characterized by the atleast one of, alternatively two of, alternatively each of properties (a)to (d) and, optionally, (e); an ethylene-propylene-dicyclopentadieneterpolymer characterized by the at least one of, alternatively two of,alternatively each of properties (a) to (d) and, optionally, (e); anethylene-propylene-ethylidene norbornene terpolymer characterized by theat least one of, alternatively two of, alternatively each of properties(a) to (d) and, optionally, (e); or an ethylene-propylene-vinylnorbornene terpolymer characterized by the at least one of,alternatively two of, alternatively each of properties (a) to (d) and,optionally, (e); respectively. An example of a suitable EPDM is anethylene-propylene-diene terpolymer made using a molecular catalyst andhaving 72.0 wt % ethylenic monomeric content measured according to ASTMD3900B and a melt index (190° C., 2.16 kg) of 1.0 g/10 min.; obtainedcommercially as VISTALON EPDMs such as VISTALON 722 from ExxonMobil; thediene may be 1,4-hexadiene, VNB, or ENB. Another example is EPDM is anethylene-propylene-diene terpolymer made using a molecular catalyst;obtained commercially from The Dow Chemical Company as NORDEL IP EPDMssuch as NORDEL IP 3722P EL Hydrocarbon Rubber having 71 wt % ethylenicmonomeric unit level and less than 1 wt % ENB comonomeric unit level.The ENB wt % may be measured according to ASTM D6047.

In some aspects the comonomer used to make the (A) crosslinkableethylene/alpha-olefin copolymer or the (D) supplemental polymer mayfurther include an olefin-functional hydrolyzable silane such as thehydrolyzable silane monomer of paragraph [0019] of WO 2016/200600 A1(PCT/US16/033879 filed May 24, 2016) to Chaudhary; or of U.S. Pat. No.5,266,627 to Meverden et al. The olefin-functional hydrolyzable silanemay be grafted (post-reactor) onto copolymer (A) or onto supplementalpolymer (D). Alternatively, the olefin-functional hydrolyzable silanemay be copolymerized with ethylene, alpha-olefin, and optionally asecond comonomer such as the second alpha-olefin or non-conjugateddiene, to directly make the (A) crosslinkable ethylene/alpha-olefincopolymer containing hydrolyzable silyl groups. Alternatively, theolefin-functional hydrolyzable silane may be copolymerized with ethyleneand an unsaturated carboxylic ester comonomer to directly make the (D)embodiment crosslinkable ethylene/unsaturated carboxylic ester copolymercontaining hydrolyzable silyl groups. In some aspects theolefin-functional hydrolyzable silane is vinyltrimethoxysilane (VTMS),vinyltriethoxysilane (VTES), vinyltriacetoxysilane, orgamma-(meth)acryloxy propyl trimethoxy silane and the hydrolyzable silylgroups are 2-trimethoxysilylethyl, 2-triethoxysilylethyl,2-triacetoxysilylethyl, or 3-trimethoxysilylpropyloxycarbonylethyl or3-trimethoxysilylpropyloxycarbonylpropyl.

Other embodiments of (A) crosslinkable ethylene/alpha-olefin copolymer,its properties and amounts are described earlier and exemplified in theinventive examples later. The (A) crosslinkable ethylene/alpha-olefincopolymer having at least one of, alternatively two of, alternativelyeach of properties (a) to (d) and, optionally, (e) are generally knownand may be obtained from commercial suppliers (e.g., The Dow ChemicalCompany) or may be made by copolymerizing ethylene and one or moreolefin-functional comonomer, with or without a catalyst, to give thecopolymer.

Polymerization methods suitable for making (A) crosslinkableethylene/alpha-olefin copolymer and (D) supplemental polymer aregenerally well-known. For example, the crosslinkableethylene/alpha-olefin copolymer may be made by copolymerizing ethyleneand one or more olefin-functional comonomers in a reactor at lowpressure (e.g., with catalyst) or high pressure (e.g., without catalyst)to give the (A) crosslinkable ethylene/alpha-olefin copolymer.Alternatively, the (A) crosslinkable ethylene/alpha-olefin copolymer maybe made by a post-reactor grafting method such as reactive extrusion ofa polyethylene with a comonomer such as the olefin-functionalhydrolyzable silane, optionally initiated or accelerated with peroxidesor catalysts, to make a graft copolymer form of the (A) crosslinkableethylene/alpha-olefin copolymer. (D) supplemental polymer, especiallythe ethylenic polymers, may be made in an analogous manner.

The constituent (B): triallyl phosphate or TAP is a compound of formulaO═P(OCH₂C(H)═CH₂)₃. It is commercially available. Embodiments of the (B)TAP and its amounts are described earlier and exemplified in theinventive examples later.

The constituent (C): organic peroxide. The (C) organic peroxide may be0.05 to 4.5 wt %, alternatively 0.1 to 3 wt %, alternatively 0.5 to 2.5wt % of the peroxide-curable ethylene copolymer composition. The (C)organic peroxide may be of formula R^(O)—O—O—R^(O), wherein each R^(O)independently is a (C₁-C₂₀)alkyl group or (C₆-C₂₀)aryl group. Each(C₁-C₂₀)alkyl group independently is unsubstituted or substituted with 1or 2 (C₆-C₁₂)aryl groups. Each (C₆-C₂₀)aryl group is unsubstituted orsubstituted with 1 to 4 (C₁-C₁₀)alkyl groups. The (C) organic peroxidemay be any one of the organic peroxides described earlier, or acombination of any two or more thereof. In some aspects only a singletype of (C) organic peroxide is used, e.g., a 20:80 (wt/wt) blend oft-butyl cumyl peroxide and bis(t-butyl peroxy isopropyl)benzene (e.g.,LUPEROX D446B, which is commercially available from Arkema),alternatively dicumyl peroxide (e.g., PERKADOX BC-FF from AkzoNobel).

The optional constituent (D) supplemental polymer selected from anethylene/unsaturated carboxylic ester copolymer, polyethylenehomopolymer, Non-(molecular catalyst)-formed ethylene/alpha-olefincopolymer, and propylene-based polymer. A polyethylene homopolymerconsists of ethylene monomeric units. A Non-(molecular catalyst)-formedethylene/alpha-olefin copolymer comprises ethylene monomeric units andolefin comonomeric units. In some aspects the Non-(molecularcatalyst)-formed ethylene/alpha-olefin copolymer is made bycopolymerizing ethylene and an alpha-olefin with a Ziegler-Nattacatalyst or without any catalyst, as in a high pressure polymerization.The polyethylene homopolymer or Non-(molecular catalyst)-formedethylene/alpha-olefin copolymer may be free of covalently bonded siliconatoms, alternatively the polyethylene homopolymer or Non-(molecularcatalyst)-formed ethylene/alpha-olefin copolymer may further containhydrolyzable silyl functional groups (e.g., trimethoxysilyl groups),which may be made as described herein. A “propylene-based polymer” is apolypropylene homopolymer having only repeat units derived from themonomer propylene (CH₃CH₂═CH₂) or a propylene-based copolymer havingmonomeric units derived from the monomer propylene (CH₃CH₂═CH₂) and oneor more comonomeric units derived from one or more olefin-functionalcomonomers. The propylene monomeric units comprise on average permolecule, at least 50 weight percent of the macromolecules of thepropylene-based copolymer. The comonomeric units are independentlyderived from one or more olefin-functional comonomers described earlierfor ethylene/alpha-olefin copolymers. In some aspects theolefin-functional comonomer(s) used to make the comonomeric units of thepropylene-based copolymer is/are (C₃-C₂₀)alpha-olefin(s), describedearlier and incorporated here by reference.

In some aspects (D) supplemental polymer is absent from theperoxide-curable ethylene copolymer composition, and thus from theinventive crosslinked product made therefrom. In some aspects (D) ispresent in the peroxide-curable ethylene copolymer composition and (D)is the ethylene/unsaturated carboxylic ester copolymer, alternatively(D) is the polyethylene homopolymer; alternatively (D) is theNon-(molecular catalyst)-formed ethylene/alpha-olefin copolymer;alternatively (D) is the propylene-based polymer. Theethylene/unsaturated carboxylic ester copolymer may be an ethylene/vinylcarboxylic ester copolymer such as ethylene/vinyl acetate (EVA)copolymer or an ethylene/alkyl (meth)acrylate (EAA) copolymer such asethylene/ethyl acrylate (EEA) copolymer. In some aspects (D) is presentand is a polypropylene homopolymer. In some aspects (D) is present andis a polypropylene copolymer, which typically contains at least 60 wt %,alternatively at least 70 wt %, alternatively at least 80 wt % ofpropylene monomeric units; at least 1 wt % comonomeric units; and atmost 40 wt %, alternatively at most 30 wt %, alternatively at most 20 wt% comonomeric units, respectively. Other embodiments of (D), itsproperties and amounts are described earner and exemplified in aninventive example later.

Examples of polyethylene homopolymers useful as (D) are low densitypolyethylene (LDPE), density 0.910 to 0.940 g/cm³, and high densitypolyethylene, density up to 0.965 g/cm³. Ethylene-based copolymers notmade with molecular catalysts that are useful as (D) are made bycopolymerizing ethylene and olefin-functional comonomers with anon-(molecular catalyst) or without a catalyst. Alternatively, (D) mayhave a melt index (190° C., 2.16 kg) of from 2 to 60 g/10 min.,alternatively 5 to 40 g/10 min. measured according to ASTM D1238-04.

Optional constituents (E) to (O). Optionally, the peroxide-curableethylene copolymer composition, and/or the crosslinkedethylene/alpha-olefin copolymer made therefrom by curing same, maycontain zero, one, or more additives and/or zero, one or more liquidaromatic or saturated hydrocarbons (LASH). Any constituent (G) to (O),when present, may be independently from >0.00 to 2.00 wt %,alternatively 0.01 to 1.00 wt % of the peroxide-curable ethylenecopolymer composition.

The optional constituent (E) antioxidant. The (E) antioxidant functionsto provide antioxidizing properties to the peroxide-curable ethylenecopolymer composition and/or peroxide-cured semiconducting product.Examples of suitable (E) are bis(4-(1-methyl-1-phenylethyl)phenyl)amine(e.g., NAUGARD 445); 2,2′-methylene-bis(4-methyl-6-t-butylphenol) (e.g.,VANOX MBPC); 2,2′-thiobis(2-t-butyl-5-methylphenol (CAS No. 90-66-4,commercially LOWINOX TBM-6); 2,2′-thiobis(6-t-butyl-4-methylphenol (CASNo. 90-66-4, commercially LOWINOX TBP-6);tris[(4-tert-butyl-3-hydroxy-2,6-dimethylphenyl)methyl]-1,3,5-triazine-2,4,6-trione(e.g., CYANOX 1790); pentaerythritoltetrakis(3-(3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl)propionate (e.g.,IRGANOX 1010, CAS Number 6683-19-8);3,5-bis(1,1-dimethylethyl)-4-hydroxybenzenepropanoic acid2,2′-thiodiethanediyl ester (e.g., IRGANOX 1035, CAS Number 41484-35-9);and distearyl thiodipropionate (“DSTDP”). In some aspects (E) isbis(4-(1-methyl-1-phenylethyl)phenyl)amine (e.g., NAUGARD 445, which iscommercially available from Addivant, Danbury, Conn., U.S.A.). (E) maybe 0.01 to 1.5 wt %, alternatively 0.05 to 1.2 wt %, alternatively 0.1to 1.0 wt % of the peroxide-curable ethylene copolymer composition.

The optional constituent (F) coagent that is not TAP. The (F) may be acompound having on average per molecule one or more —CH₂═CH₂ groups.Examples of (F) are described above. In some aspects (F) is theunsaturated organophosphorous compound. In some aspects (F) isalpha-methyl styrene dimer (AMSD) or a diisopropenylbenzene (DIPB) ortriallyl isocyanurate (TAIC). AMSD may be, e.g., Nofmer MSD from NOFCorporation and is also known as 2,4-diphenyl-4-methyl-1-pentene (CAS6362-80-7). The DIPB may be 1,3-diisopropenylbenzine (1,3-DIPB, CAS3748-13-8, Sigma-Aldrich). When present, (F) may be in a concentrationof from 0.05 to 1.0 wt %, alternatively 0.10 to 0.90 wt %, alternatively0.1 to 0.60 wt % of the peroxide-curable ethylene copolymer composition.

The optional constituent (H) hindered amine stabilizer. The (H) is acompound that has a sterically hindered amino functional group andinhibits oxidative degradation and can also reduce acid-catalyzeddegradation, if any, of (C) organic peroxide. Examples of suitable (H)are butanedioic acid dimethyl ester, polymer with4-hydroxy-2,2,6,6-tetramethyl-1-piperidine-ethanol (CAS No. 65447-77-0,commercially LOWILITE 62).

The optional constituent (I) flame retardant. (I) decreases flammabilityof the crosslinked ethylene/alpha-olefin copolymer. Examples of a flameretardant are organohalogen compounds, including brominated flameretardants, inorganic synergist compounds such as antimony trioxide,organophosphorous compounds, inorganic phosphorous compounds, metalhydrates, metal carbonates, and mixtures of any two or more thereof.

The optional constituent (J) water tree retardant or electrical treeretardant. The water tree retardant is a compound that inhibits watertreeing, which is a process by which polyolefins degrade when exposed tothe combined effects of an electric field and humidity or moisture. Theelectrical tree retardant is a compound that inhibits electricaltreeing, which is an electrical pre-breakdown process in solidelectrical insulation due to partial electrical discharges. Electricaltreeing can occur in the absence of water. Water treeing and electricaltreeing are problems for electrical cables that contain a coatedconductor wherein the coating contains a polyolefin. The (J) may be apoly(ethylene glycol) (PEG).

The optional constituent (K) colorant. E.g., a pigment or dye. E.g.,titanium dioxide.

Constituent (N) scorch retardant. Examples of a scorch retardant areallyl-containing compounds described in U.S. Pat. No. 6,277,925B1,column 2, line 62, to column 3, line 46.

Constituent (O) filler. The (O) filler may be a calcined clay, anorganoclays, carbon black, titanium oxide, or a hydrophobized fumedsilica such as those commercially available under the CAB-O-SIL tradename from Cabot Corporation. The (O) filler may have flame retardingeffects.

Other embodiments of constituents (E) to (O), their properties andamounts are described earner and, for constituents (E), (F), (H), and(J), exemplified in inventive examples later. Constituents (E) and (H)to (K), and (N) are additives that may be used to impart to either tothe composition and/or to the product, one or more beneficial propertiesother than to crosslink density. The (G) PDMS fluid is an additive thatmay be sprayed on pellets of the peroxide-curable ethylene copolymercomposition to enhance extrusion thereof. The (L) LASH(s) is an additivethat may be used to make, purge, or carry the peroxide-curable mercomposition or crosslinked ethylene/alpha-olefin copolymer. Constituents(E) to (O) are distinct compounds/materials from constituents (A) to (D)and from each other. Additives typically are not removed from thecrosslinked ethylene/alpha-olefin copolymer. (G) PDMS fluid and (L) LASHare chemically inert and may be volatile and removable.

In addition the peroxide-curable ethylene copolymer composition mayfurther comprise 0.005 to 0.5 wt % each of one or more optionaladditives selected from a carrier resin, a corrosion inhibitor (e.g.,SnSO₄), lubricant, processing aid, anti-blocking agent, anti-staticagent, nucleating agent, slip agent, plasticizer, tackifier, surfactant,extender oil, acid scavenger, voltage stabilizer, antioxidant, and metaldeactivator.

To facilitate mixing of the constituent (A) crosslinkableethylene/alpha-olefin copolymer with the constituents (B) and (C) andany optional constituents (D) to (O), one or more of the constituents(B) and (D) and any constituents (D) to (O) may be provided in the formof an additive masterbatch. The additive masterbatch may contain adispersion of (B) and (C) and optionally one or more of (D) to (O) in acarrier resin. The carrier resin may be an EVA copolymer, an EAAcopolymer, or a poly(1-butene-co-ethylene) copolymer. The amount ofcarrier resin incorporated into the peroxide-curable ethylene copolymercomposition may be from 0 to <10 wt %, alternatively 0 wt %,alternatively from >0 to 5 wt %. In the additive masterbatch, thecarrier resin may be from ≥90 wt % to <100 wt % and the (B) and (C) andany optional one or more constituents (D) to (O) together may be from >0wt % to ≤10 wt % of the total weight of the additive masterbatch. Insome aspects from 1 to 20 weight parts of the additive masterbatch maybe mixed or blended with from 99 to 80 weight parts of granules of the(A) crosslinkable ethylene/alpha-olefin copolymer to give a preparativemixture or blend thereof, which may then be pelletized according to themethods described here to give pellets. The pellets may then contactedwith a suitable amount of the (C) organic peroxide to give theperoxide-curable ethylene copolymer composition. Alternatively, (C)organic peroxide may be included in the additive masterbatch andtemperature of the additive masterbatch during its preparation andmixing with (A) may be kept well below a 10-hour half-life temperatureof the (C).

The crosslinked ethylene/alpha-olefin copolymer. The crosslinkedethylene/alpha-olefin copolymer contains networked polyolefinic resinsthat contain C—C bond crosslinks formed during curing of theperoxide-curable ethylene copolymer composition. The networkedpolyolefinic resins comprise products of coupling the (A) crosslinkableethylene/alpha-olefin copolymers or, when present, (D) supplementalpolymer. Other approaches for crosslinking of the ethylene/alpha-olefincopolymer or, when present, (D) may also be utilized, includingradiation crosslinking and, in embodiments wherein (A) and/or (D)contains hydrolyzable silyl groups as discussed earlier,moisture-induced crosslinking. The crosslinked ethylene/alpha-olefincopolymer may also contain by-products of curing such as alcoholproducts of the reaction of the (C) organic peroxide. When theperoxide-curable ethylene copolymer composition further contains one ormore of any optional constituents (D) to (O), the crosslinkedethylene/alpha-olefin copolymer may also contain the any one or more ofthe optional constituents (D) to (O), or one or more reaction productsformed therefrom during the curing of the peroxide-curable ethylenecopolymer composition. Any (L) LASH(s) and any other volatile compounds(e.g., unreacted comonomer) may be removed from the crosslinkedethylene/alpha-olefin copolymer to give a crosslinkedethylene/alpha-olefin copolymer that is independently free of, orcontains from >0 to <1 wt % of each of LASH and any other volatilecompounds. Such removal may be performed by any suitable means such asdecantation, devolatilization, distillation, evaporation, filtration,sparging with inert gas (e.g., anhydrous N₂ gas), and stripping. Thecrosslinked ethylene/alpha-olefin copolymer may be in a divided solidform or in continuous form. The divided solid form may comprisegranules, pellets, powder, or a combination of any two or more thereof.The continuous form may be a molded part (e.g., blow molded part) or anextruded part (e.g., a coated conductor or a cable).

The coated conductor. The coated conductor may be an insulatedelectrical/optical conductor, which may be an insulated electricalconductor, insulated optical conductor, or insulated electro-opticalconductor. The insulated optical conductor may include coated opticalfibers and/or optical fiber (fiber optic) cables for use indata-transmitting applications. The insulated electrical conductor mayinclude coated metal wires and/or electrical cables, including powercables, for use in low, medium, high and extra-high voltageelectricity-transmitting applications. The insulated electro-opticalconductor may include a coated combination of optical fibers and metalwires for using in both data-transmitting and electricity-transmittingapplications. A “wire” means a single strand or filament of conductivematerial, e.g., conductive metal such as copper or aluminum, or a singlestrand or filament of optical fiber. A “cable” and “power cable” aresynonymous and mean an insulated conductor comprising at least one wireor optical fiber, or a combination thereof, disposed within a coveringthat may be referred to as a sheath, jacket (protective outer jacket),or coating. When the insulated conductor contains a wire, it may becalled an insulated electrical conductor; when it contains an opticalfiber, it may be called an insulated optical conductor. The insulatedelectrical conductor may be designed and constructed for use in medium,high, or extra-high voltage applications. Examples of suitable cabledesigns are shown in U.S. Pat. Nos. 5,246,783; 6,496,629; and 6,714,707.

The insulated electrical/optical conductor may contain a conductor coreand an outer single layer covering or an outer multilayer coveringdisposed therearound so as to protect and insulate the conductor corefrom external environments. The conductor core may be composed of one ormore metal wires, one or more optical fibers, or a combination thereof.When the conductor core contains two or more metal wires and/or opticalfibers, the metal wires may be sub-divided into discrete wire bundlesand the optical fibers may be sub-divided into discrete fiber bundles.Each wire or optical fiber in the conductor core, whether bundled ornot, may be individually coated with an insulation layer and/or thediscrete bundles may be coated with an insulation layer. The singlelayer covering or multilayer covering (e.g., a single layer ormultilayer coating or sheath) primarily functions to protect or insulatethe conductor core from external environments such as sunlight, water,heat, oxygen, other conductive materials (e.g., to preventshort-circuiting), and/or other corrosive materials (e.g., chemicalfumes).

The single layer or multilayer covering from one insulatedelectrical/optical conductor to the next may be configured differentlydepending upon their respective intended uses. For example, viewed incross-section, the multilayer covering of the insulated electricalconductor may be configured sequentially from its innermost layer to itsoutermost layer with the following components: an inner semiconductinglayer, a crosslinked polyolefin insulation layer comprising thecrosslinked ethylene/alpha-olefin copolymer (inventive crosslinkedproduct), an outer semiconducting layer, a metal shield, and aprotective sheath. The layers and sheath are circumferentially andcoaxially (longitudinally) continuous. The metal shield (ground) iscoaxially continuous, and circumferentially either continuous (a layer)or discontinuous (tape or wire). Depending on the intended applicationthe multilayer covering for the insulated optical conductor may omit thesemiconducting layers and/or the metal shield, but may include alight-blocking material to prevent cross-talk between optical fibersand/or a stiffening material such as polymer fibers or bundles thereofto prevent overbending leading to breaking of the optical fibers. Theouter semiconducting layer, when present, may be composed of aperoxide-crosslinked semiconducting product that is strippable from thecrosslinked polyolefin layer.

The method of conducting electricity. The inventive method of conductingelectricity may use the inventive coated conductor that comprises theinsulated electrical conductor embodiment or the insulatedelectro-optical conductor embodiment.

Advantageously we discovered that the crosslinked ethylene/alpha-olefincopolymer product (inventive crosslinked product) exhibits sufficientflexibility and satisfactory heat or oxidative stability for use as thecrosslinked polyolefin insulation layer of the single layer covering orthe multilayer covering of the insulated electrical/optical conductor.The peroxide-curable ethylene copolymer composition (inventivecomposition) is useful for making the inventive crosslinked product.After the inventive composition is cured the resulting inventivecrosslinked product may be characterized by an enhanced (i.e.,increased) TER (7 d or 28 d, 136° C.), an enhanced (i.e., increased) OIT(O₂, 185° C.), and/or an unchanged or less than three times worsened(i.e., <3× increased), alternatively an unchanged or less than two timesworsened (i.e., <2× increased) DF (130° C., 60 Hz, 2 kV), all relativeto a TAP-free comparative composition and TAP-free comparativecrosslinked product made therefrom. In some aspects the crosslinkedethylene/alpha-olefin copolymer product is further defined by any one oflimitations (i) to (iii): (i) characterized by TER (7 d or 28 d, 136°C.) of at least 20%, alternatively at least 40%, alternatively at least50%, alternatively at least 60%, alternatively at least 65%; and at most200%, alternatively at most 150%, alternatively at most 120%,alternatively at most 110%, alternatively at most 100%; (ii)characterized by OIT (O₂, 185° C.) of at least 6 minutes, alternativelyat least 10 minutes, alternatively at least 20 minutes, alternatively atleast 30 minutes; and at most 60 minutes, alternatively at most 50minutes, alternatively at most 45 minutes; and (iii) both (i) and (ii).In some aspects the crosslinked ethylene/alpha-olefin copolymer productis further defined by (iv) a DF (130° C., 60 Hz, 2 kV) of from 0.05% to1.10%, alternatively 0.10% to 1.10%, alternatively 0.50% to 1.10%. Insome aspects the inventive composition is characterized by the inventivecrosslinked product made therefrom, and the inventive crosslinkedproduct is characterized by any one of the foregoing limitations (i) to(iv). In contrast a non-inventive comparative crosslinked product madefrom a non-inventive comparative peroxide-curable ethylene copolymercomposition that is compositionally identical to the inventivecomposition except that the comparative composition is free of (does notcontain) triallyl phosphate may be characterized by TER (7 d or 28 d,136° C.) less than 50%, alternatively less than 40%, alternatively lessthan 30%, alternatively less than 20%; and/or by OIT (O₂, 185° C.) of atmost 10 minutes, alternatively at most 5 minutes. The inventiveinsulated electrical/optical conductor is useful for data-transmittingapplications and/or for electricity-transmitting applications, includinglow, medium, high, and ultra-high voltage applications.

The inventive composition (e.g., of aspects 1 to 7) and product (e.g.,of aspect 9 to 11) are useful in a variety of applications including asa component of a coating of the coated conductor (e.g., the insulatedelectrical conductor) such as a coated wire or coated cable for use inthe electrical or telecommunications industry, including medium voltage,high voltage, and extra-high voltage electrical cables. E.g., mediumvoltage electrical cables.

Test samples of embodiments of unfilled and filled compositions may beseparately made into compression molded plaques. The mechanicalproperties of these compositions may be characterized using test samplescut from the compression molded plaques.

Olefin polymerization catalysts include Ziegler-Natta catalysts, Chromecatalysts, and molecular catalysts. Ziegler-Natta (Z-N) such asTiCl₄/MgCl₂ and Chrome catalysts such as a chromium oxide/silica gel areheterogeneous in that their catalytic sites are not derived from asingle molecular species. Heterogeneous catalysts produce polyolefinswith broad molecular weight distributions (MWD) and broad chemicalcomposition distributions (CCD). A molecular catalyst is homogeneous inthat it theoretically has a single catalytic site that is derived from aligand-metal complex molecule with defined ligands and structure. As aresult, molecular catalysts produce polyolefins with narrow CCD andnarrow MWD, approaching but in practice not reaching the theoreticallimit of Mw/Mn=2. Metallocenes are molecular catalysts that containunsubstituted cyclopentadienyl ligands (Cp). Post-metallocene arederivatives of metallocenes that contain one or more substituted CPligands, such as constrained geometry catalysts, or are non-sandwichcomplexes. Examples of post-metallocene catalysts are bis-phenylphenoxycatalysts, constrained geometry catalysts, imino-amido type catalysts,pyridyl-amide catalysts, imino-enamido catalysts, aminotroponiminatocatalysts, amidoquinoline catalysts, bis(phenoxy-imine) catalysts, andphosphinimide catalysts.

Composition Preparation Methods. Melt blend constituents of theperoxide-curable ethylene copolymer composition (of comparative orinventive examples) either in a Banbury compounder using a typicalcompounding temperature of 150° C., rotor speed of 60 to 65 rotationsper minute (rpm) or in a ZKS twin-screw extruder using an extrusiontemperature of 160° C. or higher (e.g., 200° C.) and a screw speed ofe.g., 200 rpm. For laboratory scale procedures, use batch mixers andsingle screw extruders for melt blending and pelletizing. Soak peroxideand any other liquid additives into the pellets containing blendedadditives at 50° to 80° C. for 6 to 24 hours. Preparation Method 1 belowis an example of a laboratory scale procedure.

Compression Molded Plaque Preparation Method: a crosslinked product maybe prepared in the form of a compression molded plaque by compressionmolding plaques of different thicknesses depending on testing protocol(e.g., a 50 mil (1.3 mm) thick plaque for dissipation factor testing) ofa peroxide-curable ethylene copolymer composition at the followingconditions: 500 psi (3.4 MPa) at 125° C. for 3 minutes, followed by 2500psi (17 MPa) at 180° C. for 20 minutes, then cool to 30° C. at 2500 psipressure, thereby giving a compression molded plaque form of thecrosslinked product.

Density Test Method: measured according to ASTM D792-13, Standard TestMethods for Density and Specific Gravity (Relative Density) of Plasticsby Displacement, Method B (for testing solid plastics in liquids otherthan water, e.g., in liquid 2-propanol). Report results in units ofgrams per cubic centimeter (g/cm³).

Dissipation Factor Test Method 1 for DF (130° C., 60 Hz, 2 kV): measuredaccording to ASTM D150-11, Standard Test Methods for AC LossCharacteristics and Permittivity (Dielectric Constant) of SolidElectrical Insulation, except for the differences described here.Conducted on crosslinked circular specimens cut from 50 mil (1.3 mm)thick plaques. The plaques were degassed in a vacuum oven at 60° C. forfive days. Used a GUILDLINE High Voltage Capacitance Bridge unit, Model9920A, with a TETTEX specimen holder and a TETTEX AG InstrumentsTemperature Control Unit. Samples were tested at 60 Hz and 2 kV appliedstress at 130° C. (alternative temperatures 25°, 40°, or 90° C.) Samemethod may be used for measuring dielectric constant. 1 day=24 hours. 1hour=60 minutes. 1 minute=60 seconds.

Dissipation Factor Test Method 2 for DF (100° C., 50 Hz, 2 kV): measuredby QS87 bridge with 10 kV power source and electrode system immersed insilicon oil in an oven by: (1) Degas crosslinked plaque at 70° C. for 1day. (2) Put the degassed plaque into the electrodes once thetemperature of electrode increase to around 100° C. (3) At 100° C.Increase voltage to 2 kV (first), then 4 kV and back to 2 kV (second).(4) measure the DF at each stress level and record the DF at 4 kv andsecond 2 kV and corresponding electrode temperature.

Flexural Modulus (2% secant) Test Method: measured at 23° C. accordingto ASTM D790-15e2, Standard Test Methods for Flexural Properties ofUnreinforced and Reinforced Plastics and Electrical InsulatingMaterials, measured at 2% strain and 0.05 inch/minute (0.127 cm/minute)on compression molded specimens of 125 mil (3.18 mm) thickness with acrosshead position, and expressed in pounds per square inch (psi) or theequivalent megapascals (MPa).

Glass transition temperature (T_(g)) and Melting Point Test Method:measured by differential scanning calorimetry (DSC) according to ASTM3418-15, Standard Test Method for Transition Temperatures and Enthalpiesof Fusion and Crystallization of Polymers by Differential Scanningcalorimetry, and expressed in degrees Celsius (° C.).

Melt index, I₂, Test Method: for ethylene-based (co)polymer is measuredaccording to ASTM D1238-04, Standard Test Method for Melt Flow Rates ofThermoplastics by Extrusion Platometer, using conditions of 190° C./2.16kilograms (kg), formerly known as “Condition E” and also known as I₂.Report results in units of grams eluted per 10 minutes (g/10 min.) orthe equivalent in decigrams per 1.0 minute (dg/1 min.). 10.0 dg=1.00 g.Melt index is inversely proportional to the weight average molecularweight of the polyethylene, although the inverse proportionality is notlinear. Thus, the higher the molecular weight, the lower the melt index.

Oxidative Induction Time Test Method for OIT (O₂, 185° C.): Measures thetime required to initiate oxidation of a test sample of a crosslinkedpolyolefin composition, made by the Compression Molded PlaquePreparation Method, under molecular oxygen atmosphere at 185° C. in adifferential scanning calorimeter (DSC). Used TA Instruments ThermalAnalysis Q-1000 DSC unit equipped with a Module DSC Standard Cell. Cutapproximately 2 mg of test sample into thin slices using a razor blade.Placed sliced test sample into an open aluminum DSC pan. Equilibratedpan/contents at 60° C. for 5 minutes under nitrogen gas flowing at 50milliliters per minute (mL/min.). Then under nitrogen gas raised thetemperature at 20° C./min. to 185° C., and held at 185° C. for 5 minutesunder nitrogen. Then switched the gas over to molecular oxygen, also ata flow rate of 50 mL/min., and recorded the elapsed time in minutes fromwhen the oxygen gas was switched on (Time 0) to the onset of asignificant exothermic peak in DSC as the oxidative induction time orOIT (O₂, 185° C.). The longer the elapsed time to OIT (O₂, 185° C.), themore resistant the test sample is to oxidative heat aging.

Tensile Elongation Retained Test Method for TER (7d or 28d, 136° C.):Measured tensile elongation (strain at break) of crosslinked but unagedsamples as well as crosslinked and heat-aged (oven) samples according toASTM D638 and UL 1581/2556. The method used a displacement rate of 20inches (51 cm) per minute and a Type IV dog bone-shaped specimen havinga nominal thickness of 70 mils (1.8 mm). Measurements were repeated fouror five times at each condition and averaged, Tensile properties aremeasured on unaged crosslinked specimens (i.e., kept at room temperatureof 23° C. after compression molding) and on heat-aged crosslinkedspecimens that were aged for 7 days or 28 days at 136° C. Heat-aging isconducted using a Type II ASTM D5423-93 Testing Mechanical ConvectionOven. The tensile elongation retained (TER) of heat-aged specimens (7 dor 28 d, 136° C.) is expressed as a percentage of the tensile elongationvalues of corresponding unaged specimens.

EXAMPLES

Constituent (A1): ethylene-1-octene copolymer characterized by a densityof 0.872 g/cm³ measured according to ASTM D792; a melt index (190° C.,2.16 kg) of 4.8 g/10 min. measured according to ASTM D1238; a flexuralmodulus (2% secant) of 1570 psi (10.8 MPa) measured according to ASTMD790-15e2; and a glass transition temperature (T_(g)) of −53° C.measured by differential scanning calorimetry (DSC) according to ASTM3418-15. Obtained commercially as Developmental XUS 38660.00 PolyolefinElastomer by The Dow Chemical Company, Midland, Mich., USA.

Constituent (A2): an ethylene/propylene/ENB terpolymer having a densityof 0.88 g/cm³ measured according to ASTM D792; an ethylene content of 67wt % measured according to ASTM D3900-17 (Standard Test Methods forRubber—Determination of Ethylene Units in Ethylene-Propylene Copolymers(EPM) and in Ethylene-Propylene-Diene Terpolymers (EPDM) by InfraredSpectroscopy); an ENB (5-ethylidene-2-norbornene) content of 4.9 wt %measured according to ASTM D6047-17 (Standard Test Methods for Rubber,Raw—Determination of 5-Ethylidenenorbornene (ENB) or Dicyclopentadiene(DCPD) in Ethylene-Propylene-Diene (EPDM) Terpolymers); and a MooneyViscosity (ML 1+4 at 125° C.) of 60 measured according to ASTM D1646-15(Standard Test Methods for Rubber—Viscosity, Stress Relaxation, andPre-Vulcanization Characteristics (Mooney Viscometer)). Available asNORDEL IP 4760 from The Dow Chemical Company.

Constituent (B1): triallyl phosphate (TAP), >96% purity, obtainedcommercially from TCI America, Portland, Oreg., USA.

Constituent (C1): dicumyl peroxide obtained commercially as PERKADOXBC-FF from AkzoNobel.

Constituent (C2): 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, available asLUPEROX® 101 from Arkema.

Constituent (D1): a polypropylene homopolymer characterized by a meltflow (230° C., 2.16 kg) of 1.8 g/10 min. measured according to ASTMD1238 and a flexural modulus (0.05 inch/minute, 1% secant) of 190,000psi (1,310 MPa) measured according to ASTM D790A. Obtained commerciallyas Braskem FF018F from Braskem.

Constituent (E1): 2,2′-thiobis(2-t-butyl-5-methylphenol (CAS No.90-66-4). Obtained commercially as LOWINOX TBM-6 from Addivant.

Constituent (F1): 2,4-diphenyl-4-methyl-1-pentene (AMSD). Obtainedcommercially as Nofmer MSD from NOF Corporation, White Plains, N.Y.,USA.

Constituent (H1): 1,3,5-triazine-2,4,6-triamine,N2,N2″-1,2-ethanediylbis[N2-[3-[[4,6-bis[butyl(1,2,2,6,6-pentamethyl-4-piperidinyl)amino]-1,3,5-triazin-2-yl]amino]propyl]-N′,N″-dibutyl-N′,N″-bis(1,2,2,6,6-pentamethyl-4-piperidinyl)-.Obtained commercially as SABOSTAB UV 119 from SABO S.p.A., Italy.

Constituent (J1): PEG 20000, a poly(ethylene glycol) having a mean M_(n)20000 g/mol and obtained commercially from Clariant, Charlotte, N.C.,USA.

Comparative Examples 1 and 2 (CE1 and CE2): see Preparation Method 1.

Comparative Example 3 (CE3): see Preparation Method 2.

Inventive Examples 1 to 4 (IE1 to 1E4): see Preparation Method 1.

Inventive Example 5 (1E5): see Preparation Method 2.

Preparation Method 1: Melted (C1) at 60° C., and into the resulting meltmixed (F1) at a 5:1 wt/wt ratio (C1)/(F1) to give a melt mixture.Separately mixed (A1), (D1) if any, (E1), (H1), and (J1) by hand in acontainer to give a solids mixture. Compound the solids mixture in a 420cm³ volume Brabender batch mixer with cam rotors at 190° C. and 40rotations per minute (rpm) for 5 minutes (after loading) to give ablend. Removed the blend from the mixer, cold pressed the blend into athin sheet, and cut the sheet into strips. Conditioned the strips in afreezer to harden, and then fed the hardened strips through a pelletizerto give pellets. Heated the pellets in a glass jar at 50° C. for 2hours, and then onto the heated pellets sprayed the (C1)/(F1) meltmixture and, for IE1 to 1E4, also sprayed (B1) to give aperoxide-curable ethylene copolymer composition in the jar. ((B1) wasnot used for CE1 or CE2.) Tumbled the jar to blend its contents for 10minutes at room temperature, and then placed the jar and its contentsinto an oven at 50° C. for 16 hours. The resulting contents were mixedin a 420 cm³ volume Brabender mixing bowl with cam rotors at 120° C. and30 rpm for 10 minutes (after loading) to give the peroxide-curableethylene copolymer compositions of IE1 to IE4 and CE1 and CE2, as thecase may be. Removed samples from the bowl, cold pressed or compressionmolded the removed samples, and characterized the cold pressed orcompression molded samples. The compositions and characterizedproperties of the peroxide-curable ethylene copolymer compositions ofIE1 to 1E4 and CE1 and CE2 are shown later in Table 1.

Cold pressed samples of the compositions were compression molded underconditions that prevented significant crosslinking, and tested for meltrheological characteristics. Conditions that prevented significantcrosslinking were pressing at 500 psi (3.5 MPa) at 120° C. for 3minutes, followed by 2500 psi (17 MPa) at 120° C. for 3 minutes, thencooling to 30° C. under the latter pressure, and opening the press andremoving the resulting compression molded plaques. Still other samplesof the compositions were compression molded under complete crosslinkingconditions to make specimens of different dimensions (see CompressionMolded Plaque Preparation Method above), and the specimens were testedfor electrical and mechanical properties. The data are shown below inTable 1.

Preparation Method 2: equilibrate Haake mixer at 100° C. Then addconstituents A2, B1 (if any), and C2 to mixer. Mix at 35 rotations perminutes (rpm) at 100° C. for 4 minutes to give a final polymer blend.Cold press the blend into an initial sheet according to below cold pressmethod. Subject initial sheet to two roll milling at 75° C. to give a 1mm thick final sheet. See Table 2.

Compression mold cold pressed samples of Preparation Method 2 underconditions that prevent significant crosslinking, and test for meltrheological characteristics. Conditions that prevented significantcrosslinking are pressing at 10 MPa at 120° C. for 2 minutes, followedby 10 MPa at 180° C. for 15 minutes, then cooling under 10 Mpa pressureto 30° C., opening the press, and removing the resulting compressionmolded plaques. Test specimens for electrical properties. The data areshown below in Table 2.

TABLE 1 Compositions and Test Results for Examples. (“0” means 0.00)Constituent (wt %) CE1 IE1 CE2 IE2 IE3 IE4 (A1) 87.80 87.30 96.48 96.2895.98 95.68 (B1) 0 0.50 0 0.20 0.50 0.80 (C1) 2.00 2.00 2.00 2.00 2.002.00 (D1) 8.68 8.68 0 0 0 0 (E1) 0.34 0.34 0.34 0.34 0.34 0.34 (F1) 0.400.40 0.40 0.40 0.40 0.40 (H1) 0.20 0.20 0.20 0.20 0.20 0.0 (J1) 0.580.58 0.58 0.58 0.58 0.58 Example Total* 100.00 100.00 100.00 100.00100.00 100.00 OIT (O₂, 185° C.) (min.) (1) 2.7 20.8 4.9 30.5 35.3 43.0(3.3){circumflex over ( )} TER (7 d, 136° C.) (%) (2a) N/M* N/M 12.994.0 67.3 86.8 TER (28 d, 136° C.) (%) (2b) N/M N/M 9.2 49.3 24.2 30.7Apparent Flexibility after 28 d, N/M N/M Not flexible flexible flexible136° C. (3) flexible, brittle Method 1 DF (130° C./60 Hz/2 kV) 0.40 0.580.57 1.04 0.92 0.73 (%) (4) (0.52){circumflex over ( )}

TABLE 2 Compositions and Test Results for Examples. (“0” means 0.00)Constituent (wt %) CE3 IE5 (A2) 98.04 97.89 (B1) 0 0.15 (C2) 1.96 1.96Example Total* 100.00 100.00 OIT (O₂, 185° C.) (min.)(1) N/M* N/M TER (7d, 136° C.) (%)(2a) 28.3 33.6 TER (28 d, 136° C.) (%)(2b) 22.3 28.3Apparent Flexibility after 28 d, 136° C. (3) flexible flexible Method 2DF (100° C./50 Hz/4 kV) 22.55 9.93 Method 2 DF (100° C./50 Hz/2 kV)18.48 7.80

*may not add to 100.00 due to rounding. **N/M=not measured. {circumflexover ( )}repeated CE2. (1) Oxidative induction time, in minutes, duringheating in oxygen atmosphere at 185° C. (2) Tensile Elongation Retained,in percent (%), after heating (a) 7 days or (b) 28 days at 136° C. (3)apparent flexibility measured by horizontally holding the heat agedspecimen at one end, and observing the extent to which the other enddoes not bend (not flexible) or bends ((very) flexible) under its ownweight. (4) dissipation factor, in percent (%), tested at 130° C., 60Hz, 2 kV (Table 1) or at 100° C., 50 Hz, 4 kV or 2 kV (Table 2).

The data in Table 1 show the crosslinked ethylene/alpha-olefin copolymerproduct made from the respective peroxide-curable ethylene copolymercompositions (examples IE1 to 1E4) exhibit heat and/or oxidativestability sufficient for use as the crosslinked polyolefin insulationlayer of the multilayer covering of the insulated electrical/opticalconductor. The examples 1E2 to 1E4 are characterized by enhanced (i.e.,increased) TER (7 d or 28 d, 136° C.), enhanced (i.e., increased) OIT(O₂, 185° C.), and an unchanged or less than two times worsened (i.e.,<2× increased) DF (130° C., 60 Hz, 2 kV), all relative to the respectiveTAP-free comparative examples CE1 and CE2. The example 1E1 ischaracterized by enhanced (i.e., increased) OIT (O₂, 185° C.), and lessthan two times worsened (i.e., <2× increased) DF (130° C., 60 Hz, 2 kV),and is expected to have enhanced (i.e., increased) TER (7 d or 28 d,136° C.), all relative to the respective TAP-free comparative exampleCE1. Compare IE1 to CE1 and compare 1E2 to 1E4 to CE2. Compositions CE1and CE2 were compositionally identical to compositions IE1 or IE2 toIE4, respectively, except compositions CE1 and CE2 lack triallylphosphate, whereas compositions IE1 to 1E4 contained triallyl phosphate.

Comparing CE3 and IE 5 in Table 2, triallyl phosphate also enhanced(i.e., decreased) DF (100° C., 50 Hz, 4 kV or 100° C., 50 Hz, 2 kV) incrosslinked ethylene/alpha-olefin/diene terpolymer, and did so with adifferent organic peroxide, (C2), than (C1).

1. A peroxide-curable ethylene copolymer composition comprising 58.00 to99.90 weight percent (wt %) of (A) a crosslinkable ethylene/alpha-olefincopolymer (“copolymer (A)” or “constituent (A)”), which is made by aprocess comprising copolymerizing ethylene and an alpha-olefincomonomer, and optionally another comonomer selected from anon-conjugated diene and a second alpha-olefin, in the presence of amolecular catalyst useful therefor; from 0.050 to 0.949 wt % of (B)triallyl phosphate (TAP); from 0.050 to 5.00 wt % of (C) an organicperoxide; and from 0.00 to 40 wt % of (D) a supplemental polymerselected from an ethylene/unsaturated carboxylic ester copolymer, apolyethylene homopolymer, a Non-(molecular catalyst)-formedethylene/alpha-olefin copolymer, and a propylene-based polymer; with theproviso that the total weight of constituent (A) and constituent (D) is80.00 to 99.90 wt %; wherein all wt % are based on total weight of theperoxide-curable ethylene copolymer composition and wherein total weightof the peroxide-curable ethylene copolymer composition is 100.0 wt %. 2.The composition of claim 1 further described by any one of limitations(i) to (ii): (i) the alpha-olefin comonomer is a (C₃-C₂₀)alpha-olefinand the (A) crosslinkable ethylene/alpha-olefin copolymer is anethylene-(C₃-C₂₀)alpha-olefin copolymer (e.g., bipolymer (copolymerizingwithout the another comonomer) or terpolymer (copolymerizing with thesecond alpha-olefin comonomer)) that is characterized by at least one ofthe properties (a) to (c): (a1) a flexural modulus (2% secant) offrom >0 to 40,000 psi (>0 to 278 MPa) measured according to ASTMD790-15e2 and/or (a2) a density from 0.850 to 0.930 grams per cubiccentimeter (g/cm³) measured according to ASTM D792; (b) a glasstransition temperature (T_(g)) of −130° to −20° C. measured bydifferential scanning calorimetry (DSC) according to ASTM 3418-15, and(c) a melt index (190° C., 2.16 kilograms (kg), “I₂”) of 0.5 decigramper minute (dg/min.) to 50 dg/min measured according to ASTM D1238-04;or (ii) the alpha-olefin comonomer is propylene and the anothercomonomer is used and is a non-conjugated (C₆-C₂₀)diene and the (A)crosslinkable ethylene/alpha-olefin copolymer is anethylene-propylene-(C₆-C₂₀)diene copolymer (e.g., terpolymer) (EPDM)characterized by at least one of the properties (a) to (c): (a1) aflexural modulus (2% secant) of from >0 to 20,000 psi (>0 to 138 MPa)measured according to ASTM D790-15e2 and/or (a2) a density from 0.850 to0.910 g/cm³ measured according to ASTM D792; (b) a glass transitiontemperature (T_(g)) of −130° to −20° C. measured by differentialscanning calorimetry (DSC) according to ASTM 3418-15, and (c) a meltindex (190° C., 2.16 kilograms (kg), “I₂”) of 0.1 decigram per minute(dg/min.) to 50 dg/min measured according to ASTM D1238-04.
 3. Thecomposition of claim 1 further described by any one of limitations (i)to (iv): (i) the (A) crosslinkable ethylene/alpha-olefin copolymer isfrom 90 to 99 wt % of the peroxide-curable ethylene copolymercomposition, and the peroxide-curable ethylene copolymer composition isfree of (lacks) the (D) supplemental polymer; (ii) the (A) crosslinkableethylene/alpha-olefin copolymer is from 58.00 to 90.00 wt % and the (D)supplemental polymer is from 40.0 to 1.0 wt % of the peroxide-curableethylene copolymer composition; (iii) the (D) supplemental polymer is apolypropylene homopolymer; and (iv) both (ii) and (iii).
 4. Thecomposition of claim 1 further described by any one of limitations (i)to (iv): (i) the (B) triallyl phosphate (TAP) is from 0.090 to 0.940 wt%; (ii) the (B) triallyl phosphate (TAP) is from 0.100 to 0.900 wt %;(iii) the (B) triallyl phosphate (TAP) is from 0.19 to 0.849 wt %; (iv)the (B) triallyl phosphate (TAP) is from 0.200 to 0.800 wt %; whereinall wt % are based on total weight of the peroxide-curable ethylenecopolymer composition.
 5. The composition of claim 1 further describedby any one of limitations (i) to (v): (i) the (C) organic peroxide isfrom 1.0 to 4.0 wt % based on total weight of the peroxide-curableethylene copolymer composition; (ii) the (C) organic peroxide is acompound of formula R^(O)—O—O—R^(O), wherein each R^(O) independently isa (C₁-C₂₀)alkyl group or (C₆-C₂₀)aryl group; (iii) the (C) organicperoxide is bis(1,1-dimethylethyl) peroxide; bis(1,1-dimethylpropyl)peroxide; 2,5-dimethyl-2,5-bis(1,1-dimethylethylperoxy) hexane;2,5-dimethyl-2,5-bis(1,1-dimethylethylperoxy) hexyne;4,4-bis(1,1-dimethylethylperoxy) valeric acid; butyl ester;1,1-bis(1,1-dimethylethylperoxy)-3,3,5-trimethylcyclohexane; benzoylperoxide; tert-butyl peroxybenzoate; di-tert-amyl peroxide (“DTAP”);bis(alpha-t-butyl-peroxyisopropyl) benzene (“BIPB”); isopropylcumylt-butyl peroxide; t-butylcumylperoxide; di-t-butyl peroxide;2,5-bis(t-butylperoxy)-2,5-dimethylhexane;2,5-bis(t-butylperoxy)-2,5-dimethylhexyne-3,1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane;isopropylcumyl cumylperoxide; butyl 4,4-di(tert-butylperoxy) valerate;or di(isopropylcumyl) peroxide; or dicumyl peroxide; (iv) the (C)organic peroxide is dicumyl peroxide; and (v) a combination of (i) andany one of (ii) to (iv).
 6. The composition of claim 1 further describedby limitation (i) or (ii): (i) wherein the total amount of constituents(A) to (D) is 100 wt % thereof; or (ii) wherein the total amount ofconstituents (A) to (D) is less than 100 wt % thereof and theperoxide-curable ethylene copolymer composition further comprises atleast one of constituents (E) to (O): (E) an antioxidant; (F) a coagentthat is not TAP; (G) a polydimethylsiloxane (PDMS) fluid; (H) a hinderedamine stabilizer; (I) a flame retardant; (J) a tree retardant; (K) acolorant; (L) a liquid aromatic or saturated hydrocarbon (LASH); (M) amethyl radical scavenger; (N) a scorch retardant; and (O) a filler. 7.The composition of claim 6 further described by any one of limitations(i) to (vi): (i) the peroxide-curable ethylene copolymer compositionfurther comprises constituent (E) antioxidant and the (E) antioxidant isbis(4-(1-methyl-1-phenylethyl)phenyl)amine;2,2′-methylene-bis(4-methyl-6-t-butylphenol);2,2′-thiobis(2-t-butyl-5-methylphenol;2,2′-thiobis(6-t-butyl-4-methylphenol;tris[4-tert-butyl-3-hydroxy-2,6-dimethylphenyl)methyl]-1,3,5-triazine-2,4,6-trione;pentaerythritoltetrakis(3-(3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl)propionate;3,5-bis(1,1-dimethylethyl)-4-hydroxybenzenepropanoic acid2,2′-thiodiethanediyl ester; or distearyl thiodipropionate; (ii) theperoxide-curable ethylene copolymer composition further comprisesconstituent (F) coagent that is not TAP and the (F) coagent that is notTAP is triallyl isocyanurate; an unsaturated organophosphorous compoundsuch as triallyl phosphoric triamide,N-hydroxymethyl-3-dimethylphosphonopropionamide, 2-ethyl-methacrylatephosphoric acid, phosphate ester of hydroxyl ethyl methacrylate, orvinyl phosphonic acid; or alpha-methyl styrene dimer (AMSD) ordiisopropenylbenzene (DIPB); (iii) the peroxide-curable ethylenecopolymer composition further comprises constituent (H) hindered aminestabilizer and the (H) hindered amine stabilizer is1,3,5-triazine-2,4,6-triamine,N2,N2″-1,2-ethanediylbis[N2-[3-[[4,6-bis[butyl(1,2,2,6,6-pentamethyl-4-piperidinyl)amino]-1,3,5-triazin-2-yl]amino]propyl]-N′,N″-dibutyl-N,N″-bis(1,2,2,6,6-pentamethyl-4-piperidinyl)-;(iv) the peroxide-curable ethylene copolymer composition furthercomprises constituent (J) tree retardant and the (J) tree retardant is apoly(ethylene glycol) (PEG) with a number-average molecular weight(M_(n)) of 10,000 to 30000 grams/mole; (v) the peroxide-curable ethylenecopolymer composition further comprises a combination of limitations (i)to (iv); and (vi) the peroxide-curable ethylene copolymer compositionfurther comprises from 0.20 to 0.50 wt % constituent (E) wherein (E) is2,2′-thiobis(2-t-butyl-5-methylphenol, from 0.30 to 0.50 wt %constituent (F) wherein (F) is alpha-methyl styrene dimer (AMSD), from0.10 to 0.30 wt % constituent (H) wherein (H) is1,3,5-triazine-2,4,6-triamine,N2,N2″-1,2-ethanediylbis[N2-[3-[[4,6-bis[butyl(1,2,2,6,6-pentamethyl-4-piperidinyl)amino]-1,3,5-triazin-2-yl]amino]propyl]-N′,N″-dibutyl-N′,N″-bis(1,2,2,6,6-pentamethyl-4-piperidinyl)-,and from 0.40 to 0.80 wt % constituent (J) wherein (J) is a PEG having aM_(n) of 15000 to 25000 g/mol.
 8. (canceled)
 9. A method of making aperoxide-curable ethylene copolymer composition of claim 1, the methodcomprising contacting effective amounts of constituents (A) to (C), andany optional constituents (D) to (O), to give the peroxide-curableethylene copolymer composition.
 10. (canceled)
 11. A crosslinkedethylene/alpha-olefin copolymer product that is a product of curing theperoxide-curable ethylene copolymer composition claim
 1. 12. (canceled)13. A manufactured article comprising a shaped form of the crosslinkedethylene/alpha-olefin copolymer product of claim
 11. 14. A coatedconductor comprising a conductive core and an insulation layer at leastpartially covering the conductive core, wherein at least a portion ofthe insulation layer comprises the crosslinked ethylene/alpha-olefincopolymer product of claim
 11. 15. A method of conducting electricity,the method comprising applying a voltage across the conductive core ofthe coated conductor of claim 14 so as to generate a flow of electricitythrough the conductive core.